In an image forming device to which an electrophotographic method is applied, such as a printer or a copier, an image is formed on a surface of a recording medium through a process in which a developing device develops an electrostatic latent image formed on a photosensitive drum by supplying toner to the electrostatic latent image. As a developing device included in such an image forming device, the following developing devices can be considered. Namely, a developing device to which toner is supplied from the toner cartridge storing the toner and a developing device that consumes the toner stored in the developing device in advance can be considered. Once the toner stored in the toner cartridge is used up, the used toner cartridge is replaced with a new toner cartridge, which is filled with toner. Similarly, once the toner stored in the developing device is used up, the used developing device is replaced with a new developing device filled with toner.
Inside such a used toner cartridge or a used developing device, a considerable amount of developer (toner) is still remaining. From the viewpoint of resource saving, it is preferable that, in addition to the used toner cartridge or the used developer, the residual developer be reused.
For example, Patent Document 1 (Japanese Patent Laid-Open No. 2010-128184) discloses a reproduction method of a developing device such that the used developing device is refilled with developer, and thereby the developer is reproduced. According to the reproduction method of Patent Document 1, a developer can be reproduced by a simple method.
Further, Patent Document 2 (Japanese Patent Laid-Open No. 2005-037708) discloses a cartridge cleaning device. With such a cartridge cleaning device, a cartridge can be reused by efficiently and successfully suctioning and discharging the residual toner by using a dust collector.
Further, a technique has conventionally been known such that, for an image forming device such as a copier or a printer, developer remaining inside a developing device is collected during a recycling process of the developing device (cf. Patent Document 3 (Japanese Patent Laid-Open No. 2001-242704), and Patent Document 4 (Japanese Patent Laid-Open No. 2001-255730)).
Specifically, for example, Patent Document 3 discloses a technique for removing the residual toner such that, in the recycling process of the developing device, the developing roller is rotated in a direction that is opposite to a normal rotational direction, and the toner is removed from a circumferential surface of the developing roller by using a cleaning unit. Here, the circumferential surface is exposed from an opening that is facing a photosensitive drum.
However, in the reproducing method of the developing device according to Patent Document 1, the developer remaining inside the developing device and the developer that is refilled are mixed. When the two types of developer having different use histories are mixed in the developing device, since the charging characteristics of the corresponding types of developer are different from each other, it is possible that an image failure such as density unevenness occurs when a low density image (a gray image) having a large area is formed.
It is possible to prevent such a failure caused by mixing the two types of toner having different use histories by cleaning the cartridge using the cartridge cleaning device according to Patent Document 2. However, in this case, the device for collecting the residual toner may be required, and the cost may be increased.
As it is described, when a developer container for storing developer (toner) is to be reused, it is preferable to ensure a certain level of image quality by preventing a failure caused by mixing two types of toner having different use histories. On the other hand, there are some consumers who allow degradation of the image quality and request recycled products having low prices, even though the image quality is low. Therefore, for such consumers, it is effective to reuse a toner cartridge or a developing device by collecting different types of developer having different use histories and refilling the toner cartridge or the developing device with the mixed toner.
The embodiments of the present invention have been developed in view of the above-described circumstances. An objective of the embodiments of the present invention is to provide a developer container, with which residual toner can be collected without waste and can be reused, and which allows efficient recycling of the residual toner.
Further, with the conventional technique, a non-negligible amount of the developer may remain inside the developing device, even after the developer has been collected. Additionally, with the conventional technique, the developer collected from the developing device may be discarded without being reused. Such failures occur not only in a case where the developing device is reproduced (recycled) at a recycling plant, but also in a case where a new developing device is refilled with developer and an operation check of the developing device is performed at a manufacturing plant, and subsequently the developer is collected from the developing device and the developing device is packaged and shipped.
The embodiments of the present invention have been developed in view of the above problem. Another objective of the embodiments of the present invention is to provide a developer collecting method for a developing device such that developer remaining inside the developing device is effectively collected and the collected developer is reused, without being discarded.